The video above will likely be one of the cooler things you see this afternoon. Released earlier today by the TTC, it shows “Torkie” and “Yorkie”—two of the four massive tunnel-boring machines that are in the midst of digging an extension of the Spadina subway line—busting through a concrete wall in an extraction shaft near Keele Street and Murray Ross Parkway. The breakthrough was intentional; it’s part of the construction process. According to TTC spokesman Brad Ross, these extraction shafts exist so that workers can disassemble and move the machines to different launch sites. Having them plow through a wall just happens to be the tidiest way of retrieving them.

The breakthrough marks a milestone, of sorts: the two machines have now completed a pair of 1.7-kilometre tunnels between Steeles Avenue West and the future Finch West Station. The breakthrough shown in the video happened on November 29.

According to the TTC’s tunnelling progress website, Torkie and Yorkie will now be disassembled and carted over to a new launch site near Highway 407, where they’ll start digging a new section of twin tunnels between Steeles Avenue West and Vaughan Metropolitan Centre. Meanwhile, the other two boring machines (which are known as “Holey” and “Moley”) are in the process of building the southern end of the subway extension, between Downsview Station and the future Finch West Station.

Ross says there are about 2.8 kilometres of tunneling left to go: 2.2 kilometres north of Steeles Avenue West, and .6 kilometres near Sheppard Avenue West. The whole extension project is scheduled for completion in Fall 2016. It will take the Spadina line from its present-day terminus at Downsview Station all the way to Vaughan Metropolitan Centre.

So, yes, it will be nice to have all these new subway stops. But, in the meantime, videos of giant construction equipment smashing through walls like the Kool-Aid man are an acceptable substitute.